Brief Description: Mounting the Prop Hub & Spinner Assembly
The spinner is one of the most critical of the non-structural parts on the airplane and is subject to high centrifugal forces as well as pulsating loads as the cylinders of the engine deliver their power to the prop. It’s essential the spinner be centered and firmly mounted. The rear spinner mount plate is the main structural mount, and the front plate provides alignment and stability of the spinner. Because of the tapering cone shape of the spinner, the required diameter of the front plate will vary with the thickness of the prop hub. The first picture is my completed Spinner Mount Plate with the appropriate cutouts to fit around the hub. Before I mount this to the Prop Hub, I needed to verify the both the front and rear plates fit inside the Fiberglass Spinner Cone; and they did, but with no extra overlap on the rear structural plate. That is a little concerning because it means my aft cutoff measurements on the upper and lower cowls had to be perfect or the distance between the front of the cowls and the Spinner Mounting Plate might be too long or too short for adequate clearance! Before I mount the propeller, I also need to install the alternator belt (Pic 2). It’s kind of weird you remove the propeller whenever you change an alternator belt, but that’s the way it is. The Spinner Plate Assembly is mounted to the propeller hub with a total of 4 spacers, 16 washers, 4 bolts, and 4 locknuts. The instructions don’t say anything about these but I’m guessing this is how you adjust clearances of the Spinner Hub and the Cowls.
